The Mezzanine Engine is an open source engine licensed under the GPLv3 for use with 3D game development written in C++. The Mezzanine Engine is designed to be re-usable and genre agnostic, so that it can be used in as many games as possible. All of our dependencies are open source as well enabling you to understand every single bit of what our engine is doing. However, unlike many other libraries out there we do not expect snooping through source code to be the only method of understanding a library. We have rigorously documented all the components of our engine and have made available Doxygen generated documentation to help you understand our engine. WE’ve even included a couple extra manuals and articles about some higher level usage of parts of our engine, and plan to include more articles for other parts of the engine as it is developed and matures. If for whatever reason the documentation is not enough, you are free(and encouraged) to post on our forums asking for help.
He is a list of all of our sub-system dependencies:
Audio Presentation: cAudio, OpenAL
Audio Decoding: Ogg, Vorbis
GUI: Custom, based on Gorilla
XML Parsing: PugiXML
In Game Scripting: Lua
Our Mezzanine engine documentation has another page that describes the engine in slightly more detail.